1. Field of the Invention
The present invention relates generally to video projection systems. In another aspect, this invention concerns a 3D video screen which provides enhanced depth cueing. In still another aspect, this invention concerns a method for designing and/or constructing a concave 3D video screen surface.
2. Description of the Prior Art
Video projection systems are useful for a variety of applications. Most conventional video projection systems employ a relatively flat screen surface on which images are displayed. Such conventional flat video screen surfaces provide no depth cueing (i.e., 3D effect) unless multiple projectors and/or 3D stereo glasses are employed. However, the use of multiple projectors and 3D stereo glasses is cost prohibitive for most video projection applications.
It has recently been discovered that enhanced depth cueing can be provided without the use of multiple projectors or stereo glasses by employing a specially designed concave video screen. U.S. Pat. No. 6,188,517 (assigned to Phillips Petroleum Company) describes such a concave video screen. The screen described in U.S. Pat. No. 6,188,517 generally comprises a concave semi-dome ceiling section, a flat semi-circular floor section, and a semi-cylindrical wall section edgewise joined between the ceiling section and the floor section. While this configuration provides enhanced depth cueing for certain viewing applications, it has been discovered that other video applications are best viewed on modified concave video screens in order to provide maximum viewing area, minimum distortion, and maximum depth cueing.
Because different video applications require different screen designs in order to provide optimum viewing, it is important for the shape of the video screen surface to be tailored for the specific application. However, tailoring the design of a concave video screen surface to a specific application can be an arduous task because, due to its complex shape, the screen surface is difficult to define. Further, once a suitable screen surface has been designed, it can be difficult to accurately manufacture the screen due to the complexity of the screen surface shape.
It is an object of this invention to provide 3D video projection systems which are optimized for specific applications.
Another object of this invention is to provide a simplified system for defining the shape of a complex concave video screen surface.
A further object of this invention is to provide a method for designing optimized concave video screens.
A still further object of this invention is to provide a method for manufacturing optimized concave video screens.
A yet further object of the present invention is to provide optimized 3D video screens which provide enhanced depth cueing, maximum viewing area, and minimum distortion for specific viewing applications.
In accordance with one embodiment of the present invention, a method for designing a concave 3D video screen surface is provided. The screen surface extends generally inwardly from a front edge of the screen surface. The screen surface includes an equator dividing the screen surface into a normally upper portion and a normally lower portion. The design method includes the steps of: (a) determining a maximum screen width (Xmax); (b) determining a maximum screen height above the equator (Zmax); (c) determining a rounded corner radius (rc) for the front face; and (d) calculating the location of a plurality of screen surface points by inputting Xmax, Zmax, and rc into a master equation.                               y          =                                    (                                                [                                      1                    -                                          (                                                                                                    "LeftBracketingBar"                            x                            "RightBracketingBar"                                                    P                                                                          a                          P                                                                    )                                                        ]                                ·                                  b                  P                                            )                                      1              P                                      ,                  xe2x80x83                ⁢        wherein                                          a          =                                                                      X                  max                                2                            ⁢                              xe2x80x83                            ⁢              if              ⁢                              xe2x80x83                            ⁢                              "LeftBracketingBar"                z                "RightBracketingBar"                                       less than                           (                                                                    X                    max                                    2                                -                                  r                  c                                            )                                      ,                                          a          =                                                    (                                                                            X                      max                                        2                                    -                                      r                    c                                                  )                            +                                                                                                                  r                        c                        2                                            -                                                                        (                                                                                    "LeftBracketingBar"                              z                              "RightBracketingBar"                                                        -                                                          (                                                                                                                                    X                                    max                                                                    2                                                                -                                                                  r                                  c                                                                                            )                                                                                )                                                2                                                              ⁢                                          xe2x80x83                                                                      ⁢                                  xe2x80x83                                ⁢                if                ⁢                                  xe2x80x83                                ⁢                                  "LeftBracketingBar"                  z                  "RightBracketingBar"                                                      ≥                          (                                                                    X                    max                                    2                                -                                  r                  c                                            )                                      ,                                          b          =                                                    (                                  1                  -                                                            z                      2                                                              Z                      max                      2                                                                      )                            ·                                                (                                                            X                      max                                        2                                    )                                2                                                    ,                  xe2x80x83                ⁢        and                                          P          =                      2            -                          (                                                k                  ·                                      "LeftBracketingBar"                    z                    "RightBracketingBar"                                                                    Z                  max                                            )                                      ,            
wherein Xmax is in a range of from about 6 inches to about 1200 inches, wherein Zmax is in a range of from about 0.1 Xmax to about 0.5 Xmax, wherein rc is in a range of from about 0 to about 0.5 Xmax, wherein k is in a range of from 0.1 to about 0.95, wherein the screen surface extends relative to orthogonal X, Y, and Z axes, wherein x is the orthogonal distance from the Y-Z plane to the display surface, wherein y is the orthogonal distance from the X-Z plane to the display surface, wherein z is the orthogonal distance from the X-Y plane to the surface, and wherein the actual position of each point defining the display surface varies by less than 0.1 Xmax from the calculated position of the point as defined by the master equation.
In accordance with still another embodiment of the present invention, a 3D video projection system is provided. The video projection system generally comprises a housing, a concave video screen, and a projector. The video screen and projector are positioned within the housing. The projector is operable to project an image on the video screen. The housing has an opening therein through which the video screen can be viewed from outside the housing.